A Pseudo Wire (PW) provides a service emulation technology, including a point to point method and a point to multipoint method. A Provider Edge (PE) equipment performs simulation on user data through operations of encapsulation and decapsulation of received Customer Edge (CE) data.
As an edge to edge layer 2 service transport technology, the PW may be applied in a Layer 2 Virtual Private Network (L2VPN), and may be used to provide a Virtual Private Wire Service (VPWS), and a Virtual Private LAN Service (VPLS). Based on the requirements of the network interworking in the continuously extending network, strict security requirements must be guaranteed in the network. Therefore, a Multi-Segment Pseudo Wire (MS-PW) needs to be established for service transport, so as to satisfy the need of edge to edge service emulation crossing multiple Provider Service Networks (PSNs). On the other hand, because the network continuously enlarges, the number of network equipment increases accordingly. The full or partially full network connections between equipment in the network must be deployed, if point to point PW is used for service transport. This will cause certain troubles during network deployment. MS-PW which must be used to reduce the quantity of sessions between the equipment.
In particular, in a fixed-mobile convergence (FMC) network, MS-PWs are also needed. The services, such as Time Division Multiplexer (TDM) and Asynchronous Transfer Mode (ATM) must be transmitted by Pseudo Wire between Cell Site Gateway (CSG) and Mobile Aggregation Site Gateway (MASG). Because masses of CSGs, the targeted label distribution protocol (T-LDP) sessions is the challenge for MASG, MS-PWs are also required.
Currently, the MS-PW could be deployed via static configuration or dynamic protocols. During the static configuration, a MS-PW should be established segment by segment, then mapping relations between PW segments are established. As shown in FIG. 1, in order to statically configure a MS-PW between a terminal node 100 and a terminal node 140, it needs to statically configure PW105 and PW115 between the terminal node 100 and a switching node 120, and statically configure PW125 and PW135 between the switching node 120 and the terminal node 140, and then manually configure mapping relations for PW segments on the switching node 120, for example, mapping relations between PW Identifiers (IDs), such as a mapping relation between a PW ID of PW105 and a PW ID of PW125, and a mapping relation between a PW ID of PW 115 and a PW ID of PW135. Based on these static configurations, the PW between the terminal node 100 and the terminal node 140 is deployed. However, when multiple switching nodes or multiple MS-PWs exist between the terminal node 100 and the terminal node 140, the workload for manual configuration is very heavy; additionally maintenance of MS-PWs is complicated.
The PW could be established dynamically by two steps: statically configuring or dynamically establishing a PW routing table, establishing the MS-PW by using Label Distribution Protocol (LDP). As shown in FIG. 1, in order to establish PWs between the terminal node 100 and the terminal node 140, it first needs to establish a PW routing table via manually configuring or a routing protocol on the switching node 120. Then, the terminal node 100 sends LDP signaling for establishing PW segments between the terminal node 100 and the switching node 120. After receiving the LDP signaling, the switching node 120 queries the configured PW routing table, and then initiates LDP signaling for establishing PW segments between the switching node 120 and the terminal node 140. During dynamic establishment of an MS-PW, a PW routing table must be deployed on a switching via manually configuring or dynamically based on a complicated protocol Therefore, when multiple switching nodes or multiple MS-PWs exist, the workload of manually configuring the PW routing table on the switching node is very heavy. On the other hand, there is a strict capability requirement for equipment in order to introduce routing protocols. In addition, it is complicated to establish the PW routing table.